1) Field of the Invention
The present invention relates to releasable stores that are mounted on an aircraft and, more particularly, to a store ejection system having an isolation valve integral to other system components such that the isolation valve is configured to be operatively actuated by the other components, as well as an associated ejection method.
2) Description of Related Art
The term xe2x80x9cstorexe2x80x9d is used herein to refer generally to any of a number of munitions or other materials that can be dispensed from an aircraft or other vehicle or structure. For example, military aircraft can include a store ejection system to dispense bombs, missiles, rockets, and other types of munitions. Non-munitions stores can include electronic equipment and other materials. Typically, a store ejection system includes one or more racks beneath the wings or fuselage of the aircraft for holding the stores and releasing the stores upon a command. For example, store racks are described in U.S. Pat. Nos. 5,907,118 and 6,035,759, both by the same inventor and assignee as the present invention.
In one conventional store ejection system, the stores are connected to the racks by one or more mechanical hooks. The store ejection system includes a release mechanism for actuating the hooks to release the stores and a jettison mechanism for forcibly ejecting the stores away from the aircraft. The release and jettison mechanisms can be actuated by a pressure-actuator, such as a ram that is actuated by a pressure increase in a cylinder. The pressure can be provided by a pyrotechnic cartridge, i.e., an explosive, or by a source of non-pyrotechnic compressed gas. For example, U.S. Pat. No. 5,583,312 describes a system including a compressor for compressing a non-pyrotechnic gas such as air that is used to actuate ejector pistons of one or more suspension and release equipment (S and RE) modules that releasably retain and jettison stores. Alternatively, a compressed gas can be stored in a pressure vessel on the aircraft, as described in U.S. application Ser. No. 10/205,570. The flow of pressurized gas from the pressure vessel to each of the S and RE modules is typically controlled by an isolation or enable valve. Generally, the isolation valve is a solenoid-operated valve that is electrically powered and controlled between open and closed positions. In the closed position, the isolation valve prevents the flow of the pressurized gas to an accumulator of a respective S and RE module. For example, the isolation valve can be closed to prevent fluid from flowing to the accumulator of a S and RE module from which the store is presently being released or from which the store has already been released.
While the conventional systems have proven effective for controlling the ejection of stores, a need continues to exist for improvements in the physical characteristics and operational aspects of store ejection systems. For example, desirable improvements to such systems include a reduction in weight and complexity, improved efficiency, reduced power requirements, and a reduction in required components such as logic control devices and wiring.
The present invention provides an improved store ejection system for mounting a jettisonable store on an aircraft. The system includes an isolation valve that is actuated by the S and RE module to prevent a flow of pressurized fluid in response to the actuation of the S and RE module. For example, the isolation valve can be operatively coupled to the actuation system or the jettison mechanism of the S and RE module, thereby reducing the complexity of the system, increasing the efficiency of the system, and reducing the wiring and electrical logic components of the system.
According to one embodiment of the present invention, the system includes a fluid source capable of providing a pressurized non-pyrotechnic fluid for providing the source of energy and the transfer mechanism. The system also includes an actuation system having an accumulator configured to be selectively fluidly connected to the fluid source for receiving and storing the fluid therefrom. A poppet valve, which can be controlled by a controller that responds to a control signal to jettison the store, controls a flow of the fluid from the accumulator. A pneumatically-driven jettison mechanism for releasably retaining the store is fluidly connected to the poppet valve so that when the poppet valve is actuated to an open position, the pressurized fluid in the accumulator is released to flow to the jettison mechanism to jettison the store. The isolation valve is configured to control a flow of the fluid from the fluid source to the accumulator, and a valve control member is configured to operatively couple the isolation valve to an adjustable member of the actuation system or the jettison mechanism. Thus, the isolation valve is closed when the poppet valve is actuated to the open position, and the isolation valve thereby prevents the flow of the fluid from the fluid source.
One or more retention members can retain the store, and a drive member, which actuates the retention member to release the store, can be operatively coupled to the isolation valve to close the valve when the drive member actuates the retention member to release the store. For example, the drive member can be coupled to the isolation valve by a valve control member such as a pinion gear coupled to a rack gear on the drive member, the pinion gear defining a cam in communication with the isolation valve. The retention member can be actuated to release the store by a flow of the pressurized fluid exiting the accumulator through the poppet valve. In addition, the jettison mechanism can include at least one ejector piston for forcibly jettisoning the store away from the aircraft when the retention member has been actuated to a release position.
According to one aspect of the present invention, the accumulator defines a port in fluid communication with the isolation valve and the poppet valve. The accumulator is filled by the flow of fluid from the fluid source through the port, and the flow of fluid from the accumulator to the poppet valve and the jettison mechanism is also delivered through the port. The isolation valve can be located proximate to the accumulator and/or the poppet valve. For example, the isolation valve can be disposed in an integral body portion that also houses the poppet valve.
Another aspect of the present invention provides a method of jettisoning a store from an aircraft using a pressurized non-pyrotechnic fluid as a source of energy and a transfer mechanism. The store is releasably retained with at least one pneumatically-driven jettison mechanism, and a fluid is provided from a fluid source to an accumulator via an isolation valve. A poppet valve is actuated to fluidly connect the accumulator to the jettison mechanism so that the fluid flows from the accumulator to the jettison mechanism and actuates the jettison mechanism to jettison the store. For example, the poppet valve can be actuated by a controller in response to a control signal to jettison the store. The isolation valve is closed via an operative coupling between the isolation valve and the actuation system or jettison mechanism so that the isolation valve prevents a flow of the fluid from the fluid source while the poppet valve is in the open position.
According to one aspect of the invention, one or more retention members can retain the store, and the retention member can be actuated by a drive member that is operatively coupled to the isolation valve by the valve control member. For example, a rack gear on the drive member can rotate a pinion gear so that a cam on the pinion gear actuates the isolation valve. The retention member can be actuated by a flow of pressurized fluid exiting the accumulator that adjusts the poppet valve. In addition, the pressurized fluid exiting the accumulator through the poppet valve can actuate an ejector piston to forcibly jettison the store away from the aircraft.